1. Field of the Invention
The present invention relates to communication networks and, more particularly, to a method and apparatus for assigning and allocating network resources to layer 1 virtual private networks.
2. Description of the Related Art
Data communication networks may include various computers, servers, nodes, routers, switches, bridges, hubs, proxies, and other network devices coupled to and configured to pass data to one another. These devices will be referred to herein as “network elements.” Data is communicated through the data communication network by passing protocol data units, such as Internet Protocol packets, Ethernet Frames, data cells, segments, or other logical associations of bits/bytes of data, between the network elements by utilizing one or more communication links between the devices. A particular protocol data unit may be handled by multiple network elements and cross multiple communication links as it travels between its source and its destination over the network.
Communication network subscribers may at times desire to have dedicated network resources allocated through a public or other entity's network infrastructure. For example, a subscriber may wish to lease network resources, such as optical network resources, from another network operator that has already installed optical fiber and optical networking equipment. This may be advantageous for the subscriber, for example, in that it may allow the subscriber to manage and control the network resources in a manner that would not be possible if the network resources were shared with other subscribers.
There are several scenarios where it may be desirable for a subscriber to purchase or lease a portion of a deployed network. For example, a network operator may wish to enter a particular market and not incur the up front costs associated with deploying its own optical network. Alternatively, a network operator may wish to deploy the physical assets only and allow other network operators to manage the use of those network assets. An example of this scenario may be a company that installs a large optical fiber bundle across an obstacle such as the Atlantic Ocean, and then desires to allow companies to lease portions of the bandwidth for transmission of data across the ocean. The company that owns the cable may not have any interest in operating a network across that cable but rather would prefer to simply collect for allowing others to use the cable to transmit information. In these and other situations, it becomes desirable to allocate a portion of the deployed physical assets to a particular customer.
Virtual Private Networks (VPNs) at Layers 2 and 3 of the network hierarchy are able to create tunnels through an otherwise provisioned network, and allow the network to be shared by many different participants in a secure manner. These VPNs, however, do not actually obtain dedicated rights to the network resources for transmission of data associated with the VPN. Rather, the data is mixed together with other traffic and transmitted in common with other traffic on the network. For example, an MPLS VPN may be used to create a VPN tunnel across an MPLS network. RSVP-TE or another protocol may be used to reserve statistical resources for that tunnel. However, the packets that are sent over the tunnel are not sent over dedicated resources on the network, but rather are multiplexed with numerous other packets from other VPNs as they travel through the network.
Thus, although a subscriber of layer 2 or layer 3 VPN network services may be guaranteed bandwidth on a network in a statistical fashion, it does not have dedicated resources on the network to handle its traffic. Without having dedicated resources on the network, the subscriber cannot control the network resources since doing so would affect other network subscribers. The lack of control limits the subscribers ability to customize the network to accommodate its requirements, and thus requires the subscriber to request network changes from the network owner, which is generally a slow process and, more importantly, may not be possible given the shared nature of the network resources. Thus, layer 2 and 3 VPNs are not suitable for particular subscribers that may wish to exert control over the network resources.
Conventionally, to provide dedicated resources, it was necessary for the subscriber to purchase a portion of the network to create an actual private network. This required the client to obtain sufficient resources to meet its expected peak load, did not allow for resources to be shared (except at layer 2 and above) and did not provide flexibility to enable additional resources to be obtained quickly or on demand.